This project involves the study of a new pancreatic hormone called Pancreatic Polypeptide or Pancreatic Hormone III. The avian hormone (APP) is found only in pancreas (chickens) and can be localized to secretory cells scattered throughout the pancreatic parenchyma. The hormone is composed of 36 amino acid residues and apparently is synthesized as a precursor since a peptide has been isolated which contains APP and an additional 27 residues at the N-terminus. Secretion of APP is stimulated by the presence of food in the gut and this reaction is partly mediated by the vagus nerve. Atropine completely blocks secretion of the hormone and carbamyl choline stimulates secretion. In chickens APP stimulates gastric secretion, hepatic glycogenolysis and probably triglyceride synthesis. The true function of the hormone is as yet unknown.